Method of preparing nitropyridine arsinic acids



Pmaa 1 1 3, 1923.

mnim' nnrz um cun'r airs, on mannm, Gm.

.II'I'HOD OI PREPARING KI'I'BOPYBIDINE ansnnc'acms.

In Application and In as; new, Serial a. 200,170, l in Germany August a, 1m.

Attempts to nitrate substituted pyridine arsinic acids, e. g. 2-hydroxy-pyridine-5-arsinic acid, in which mild nitrating agents were used in order to avoid the b oi? 5 of the arsinic residue or the breaking own of the substituted pyridine ring, have shown that either absolute y no nitration results or that this takes place only incompletely and According to this invention it has now been shown in a arsmic acids, particularly those containing as substituente hydroxyl or halogen groups, such as 2-hydroxy-pyr1dine-5-ars1nic acid: or 2-halogen-pyridine-5-arsinic acid by the use of energetically reacting nitration methods, smoothly and with the production of good yields, mto nitro compounds, without the feared secondary reaction, such as the breaking of of the arsenic residue or the breaking place.

e nitrated pyridine arsinic acids prepared according to this invention therapeutically valuable properties; theyfurther form starting materials for the production of other valuable compounds. In this way therapeutically valuable compounds 8 can he obtained, for example by treating the nitrated arsinic acids with reducing agents. I

The following example illustrates the production of one compound according to the invention '100 grms. of 2-hydroxy-pyridine-5-arsinic acid are dissolved in 200 grins. ofconcentrated sulphuric acid. 125 grms. of red fuming nitric acid are slowly added to the hand- 0' warm solution with The nitrating mixture is next warmed for about one hour on a vigorously waterbath and then poured into 1.2 litres of water. Crystallization starts immediately. The resulting 2- hydroxy-3-nitro:pyridine-5-arsinic acid is easily lllaed from water. It is then obtained as yellowish-green plates,

;which are easilyksoluble in alkali-metal hysurprismg manner that it is possible to convert substituted pyridine down of the substituted pyridine ring takdroxide and a ali-metal carbonate. The

graphical formula of the new product is no\ no- I N0: 6 I l By the foregoing method, given byway of an example, it is possible to introduce the nitro group into the position next to the hy- "droxyl group, which so far as we are aware 00 has not up till now been attained.

The 2hydroxy-3-amino-pyridine 5-arsinic acid obtained by the reduction of the 2- hydroxy-3-nitro-pyridine-5Farsinic acid posstrong bactericidal properties, especially as regards trypanosomes, as. well as being very. non-poisonous. V g

It is known that the nitro group can be introduced into aryl-arsinic acid. The success of the forego reaction could not be concludedfrom this owever. According to Meyer and Jacobsen, vol. 2, Part III, page 843, nitric acid in some cases reacts so v gorously with pyridine compounds, which contain substituents, as, for example, the hydroxyl group, that in place of nitro derivatives, products of far reaching oxidation are obtained. It was therefore in no way to be anticipated, that in the foregoing case, even by the use of very vigorous nitrating agents, as, for example, red fuming nitric acid, neither a breaking off of arsenic nor an oxi; dizing decomposition takes place.

We claim:

1. Method of preparing nitropyridine arsinic acids, comprising the. step oftreating substituted pyridine arsinic acids with energetically reacting nitrating agents.

2. Method of preparing nitropyridine arsjnic acids, comprising the step of treating pyridine arsinicacids, which contain a hydroxyl group, with energetically react ng nitrating agents.

3. Method of preparing nitropyridlne arsinic acids, comprising the step of treating 2-hydroxy-pyridine-5-arsinie acid with energetlcally reacting nitrating agents.

4. Method of preparin nitropyridine ar sinic acids, comprislng t e step of treating pyridine ars'inic acids, which are substituted in the ortho position to the nitrogen, with energetically reacting nitrating agents.

- 5. Method of preparin nitropyridine arsinic acids, comprislng t e step of treating pyridine arsinic acids which contain a hydroxyl group in the ortho position to the nitrogen, with energetically reacting nitrating a-lgients.

6. ethod of preparing nitropyridine arsinic acids, comprising the step of treating substituted pyridine arsinic acids with red fuming nitric acid.

In testimony whereof we aflix our signatures. v

ARTHUR BINZ. CURT BATH. 

